fix(postgresql): fall back to distro packages instead of bookworm-pgdg on Trixie (#12524)

When the PGDG repo is unreachable for trixie/forky/sid, the previous
code fell back to bookworm-pgdg. This causes unresolvable dependency
errors because bookworm-pgdg packages depend on libldap-2.5-0 and
libicu72, which don't exist on Trixie (has libldap-2.6-0 and libicu76).

Instead of falling back to an incompatible suite, recursively call
setup_postgresql with USE_PGDG_REPO=false to use Debian's native
PostgreSQL packages (Trixie ships PG 17 natively).

misc/tools.func

@@ -6500,14 +6500,13 @@ function setup_postgresql() {
   local SUITE
   case "$DISTRO_CODENAME" in
   trixie | forky | sid)
-
     if verify_repo_available "https://apt.postgresql.org/pub/repos/apt" "trixie-pgdg"; then
       SUITE="trixie-pgdg"
-
     else
-      SUITE="bookworm-pgdg"
+      msg_warn "PGDG repo not available for ${DISTRO_CODENAME}, falling back to distro packages"
+      USE_PGDG_REPO=false setup_postgresql
+      return $?
     fi
-
     ;;
   *)
     SUITE=$(get_fallback_suite "$DISTRO_ID" "$DISTRO_CODENAME" "https://apt.postgresql.org/pub/repos/apt")